Conventionally, a wire-to-wire connection and a wire-to-lead connection used for a motor are electrically and mechanically established via a connection terminal. In the description below, connecting wires with each other and connecting a wire to a lead may be collectively referred to as connecting wires and the like. As a method for connecting wires and the like, Patent Literatures 1 and 2 suggest a method for crimping a connection terminal. Hereinafter, a connection terminal may be simply referred to as a terminal.
A conventional method for crimping a terminal will be described with reference to FIG. 3 through FIG. 7C.
FIG. 3 is a connecting diagram of a conventional single-phase induction motor. As shown in FIG. 3, main lead 22 is connected to main coil 20, and auxiliary lead 23 is connected to auxiliary coil 21. Common lead 24 is connected to both of main coil 20 and auxiliary coil 21. Commonly, the amount of current flown into auxiliary coil 21 is smaller than that of main coil 20. Accordingly, the wire used for auxiliary coil 21 has a wire diameter smaller than that of main coil 20.
The method of connecting each section is described with reference to FIG. 4A through FIG. 6C.
FIGS. 4A through 4C show a way of the connection of main lead 22 and main coil 20. As shown in FIGS. 4A and 4B, wire 20a forming main coil 20 and core wire 22a of main lead 22 are disposed on the inner side of terminal 25 which is a connection terminal. After wire 20a and core wire 22a are placed inside terminal 25, terminal 25 is bent inwardly. As shown in FIG. 4C, terminal 25 is crimped so as to wrap around wire 20a and core wire 22a. At that time, in crimping part 25a of terminal 25, a distorted area is formed in wire 20a and core wire 22a. When a predetermined amount of distortion is applied to wire 20a and core wire 22a, they are electrically and mechanically connected with each other.
FIGS. 5A through 5C show a way of the connection of auxiliary lead 23 and auxiliary coil 21. As shown in FIGS. 5A and 5B, wire 21a of auxiliary coil 21 and core wire 23a of auxiliary lead 23 are disposed on the inner side of terminal 25 which is a connection terminal. FIG. 5C shows a state where auxiliary lead 23 and auxiliary lead 21 are crimped by terminal 25.
FIGS. 6A through 6C show a way of the connection of common lead 24, main coil 20, and auxiliary coil 21. As shown in FIGS. 6A and 6B, wire 20a forming main coil 20, wire 21a forming auxiliary coil 21, and core wire 24a of common lead 24 are disposed on the inner side of connection terminal 25. FIG. 6C shows a state where common lead 24, main coil 20, and auxiliary coil 21 are crimped by terminal 25.
Each wire diameter of the wires and the core wires used for a single-phase induction motor is determined so as to be suitable for the amount of current that each section carries. In connecting wires and the like used for a single-phase induction motor, as shown in FIGS. 4A through 6C, wires 20a and 21a and core wires 22a, 23a and 24a to be crimped at crimping part 25a are different in cross-section area and in number of the wires. Specifically, the connection has three combinations described above.
In the situation above, when terminal 25, which is shown in FIGS. 4A to 4C, for connecting main lead 22 and main coil 20 is used for other connections in the single-phase induction motor. Then the problem below arises. That is, as shown in FIGS. 5A through 5C, terminal 25 is used for crimping auxiliary coil 21 of a small wire diameter. A gap may be happened to be formed at crimping part 25 due to large dimensions of terminal 25. If such a gap is formed at crimping part 25, auxiliary lead 23 and auxiliary coil 21 fail to have a predetermined amount of distortion, resulting in unstable connection between them.
To address the problem, as shown in FIGS. 7A through 7C, auxiliary lead 23 and auxiliary coil 21 are connected by terminal 26 having small dimensions. The dimension of terminal 26 is smaller than that of terminal 25 used for connecting wire 20a of main coil 20.
As described above, by using terminal 26 having smaller dimension than that of terminal 25 which is used for other portions, a predetermined amount of distortion is applied to crimping part 26a. Having the predetermined amount of distortion, core wire 23a and wire 21a are electrically and mechanically connected with each other via terminal 26.